It didn’t take long for New Jersey’s much-hated 23-cent gas tax hike to get worse, as revenues from the increase falter.

This also won’t be the last time we’re likely to look back on those original 23 cents as a relative bargain.

When New Jersey lawmakers struck a deal with then-Gov. Chris Christie on the tax bump in 2016, it came with conditions. Much of the attention went to the collection of tax and fee reductions Christie cobbled together to help theoretically compensate for the increase, although it’s fair to question the sincerity of that effort; scrapping the estate tax, for instance, hardly has the same effect on average New Jerseyans as the gas tax.

Also included in that legislation, however, was a provision designed to ensure that a targeted amount of revenue — about $1.2 billion annually — continues to flow into the Transportation Trust Fund. If the money comes up short, the state treasurer can adjust the tax upward — or downward if there’s a surplus.

This, however, is New Jersey, and that means taxes always go up. With current estimates showing a likely shortfall, officials are floating the prospect of another increase of at least 2 cents a gallon, possibly more.

The volatility of gas prices already masks the impact of the 23-cent hike; adding another few cents will hardly be noticed by most New Jerseyans. But this is just a start. The higher tax establishes a new baseline, and if — or when — the revenues it generates come up short again, the tax will get another bump.

It’s not clear what’s causing the shortfall. More fuel-efficient cars could be a factor, and changing driving habits. Or it could simply be a familiar New Jersey problem: overly optimistic estimates from officials trying to sell a plan. We’ve seen it over and over again, lawmakers relying on rosy projections that invariably don’t materialize, forcing more unwanted spending decisions. For those who were trying to sell a gas-tax hike to address the state’s chronic transportation funding shortage, a lower increase while quietly stacking the deck for future bumps figured to be more palatable to the public than a higher increase from the start.

Also looming is the planned expiration of the original increase — and its future adjustments — after eight years. That sunset provision was designed to give the process a sheen of impermanence, as if somehow after eight years of added revenue lawmakers would suddenly pull the plug. We all know that won’t happen, and it’s likely the tax will be renewed and bumped higher yet again.

The disingenuous quality of the entire gas-tax effort is one of the reasons some officials who supported the concept objected to the final plan. Former Assemblyman John Wisniewski, long a vocal advocate for raising the gas tax as chairman of the Assembly Transportation Committee, ridiculed the final deal not only for its eight-year framework, but also for the tax-cut tradeoffs that will only create budget problems elsewhere.